Mobile lifting equipment



July 1, 1958 J. M. EITEL MOBILE LIFTING EQUIPMENT Filed Jan. 25, 1956 IN VEN TOR. By Jay M. E TEL HTTORNEVS United States Patent Office I2,841,404 Patented July 1, 1958 MOBILE LIFTING EQUIPMENT Jay M. Eitel,Los Altos, Calif.

Application January 23, 1956, Serial No. 560,622

6 Claims. (Cl. 280-6) This invention relates generally to liftingequipment of the mobile type wherein the load supporting structure iscarried by a motorized vehicle. More particularly it relates to liftingequipment of the type wherein the load supporting structure is rotatableabout a vertical axis and utilizes a load carrying boom structure.

Suitable means must be provided with lifting equipment of this type tostabilize the equipment when the boom structure is rotated so that thecenter of gravity of the load supporting structure overlie thelongitudinal axis of the vehicle frame. In the past, Outriggers andspring locks have been utilized to stabilize the equipment, but theyhave been found to be objectionable because they must be taken out ofoperation when the vehicle is moved. They are also objectionable becausethey cannot be used to stabilize the equipment while the vehicle ismoving.

In general, it is an object of the present invention to provide liftingequipment with novel apparatus for improving the stability and liftingperformance of mobile lifting equipment.

Another object of the invention is to provide lifting equipment of theabove character in which the stabilizing apparatus need not be taken outof operation when the vehicle is being moved.

Another object of the invention is to provide lifting equipment of theabove character in which the stabilizing apparatus functions while thevehicle is moving as well as when the vehicle is stationary.

Another object of the invention is to provide lifting equipment of theabove character in which the stabilizing apparatus also serves toimprove the riding and handling characteristics of the vehicle.

Additional objects of the invention will appear from the followingdescription in which the preferred embodiment has been set forth indetail in conjunction with the accompanying drawing.

Referring to the drawing:

Figure 1 is a side elevational view of a lifting equipment incorporatingthe present invention.

Figure 2 is a perspective view of the stabilizing apparatus utlized inthe lifting equipment.

Figure 3 is a plan view of the bed plate and stabilizing apparatuswithout the supporting framework.

In general, the present invention employs one or more torsion memberswhich are mounted laterally of the frame of the vehicle and journalledto the bed plate carrying the rotatable lift supporting structure. Armsare connected to the ends of the torsion members and the ends of thearms are fastened by an articulated connection to the axle of thevehicle underlying the load supporting structure.

The lifting equipment illustrated in the drawing consists generally of amotorized vehicle 11 having front and rear wheels 12 and 13 andlaterally spaced frame members 14 and 16; The frame members are attachedto the rear axle 17, which serves as a mounting for rear Wheels 13, byload supporting cushioning assemblies 18. The cushioning assembles canbe of any suitable type well known in the art such as thesemi-elliptical spring type shown in the drawing or the coil springtype. The cushioning assemblies can also be of the hydraulic orpneumatic type.

A rigid bed plate 21 is supported on the frame members 14 and 16 bysuitable means such as by bolts (not shown) or welding. However, ifdesired, the bed plate can be supported on the frame of the vehicle insuch a manner that the frame may twist relative to the bed plate. Theprimary consideration is that loads usually imposed on the truck frameby this type of equipment are transferred directly to the axle ashereinafter described. Suitable means is provided for mounting the liftsupporting structure on the bed plate for rotational movement about avertical axis and consists of a vertical stud shaft 22, the lower end ofwhich is mounted on the bed plate 21 in such a manner that the axis ofthe shaft generally overlies the axle 17. A large ring gear 23 encirclesthe stud shaft 22 and is fixed to the mounting plate 21. The loadsupporting structure 24 is rotatably mounted on the stud shaft 22. Thering gear is used in rotating the load supporting structure about thevertical axis formed by the stud shaft 22 as described in my co-pendingapplication Serial Number 560,621, filed January 23, 1956.

As also disclosed in the above co-pending application, the loadsupporting structure consists of a cab 26 and an axially extensible boomstructure 27 which is pivoted at 28 for swinging movement about ahorizontal axis. A work cage 29 is pivotally mounted on the outer end ofthe extensible boom structure 27 and is provided with control apparatuswhereby the load supporting structure can be rotated about a verticalaxis and the boom structure raised and lowered about the horizontal axisand axially extended or retracted. The lifting equipment is alsoprovided with similar control apparatus to permit control from theground.

To stabilize the lifting equipment when the boom structure is movedsideways of the vehicle, I have provided a pair of stabilizingassemblies 34 extending laterally of the frame members 14 and 16. Eachof the stabilizing assemblies consists of a torsion bar or member 36which extends laterally of the frame members 14 and 16 adjacent one sideof the bed plate. As shown in the drawing, the ends of the torsionmember extend beyond the outer side edges of the frame members 14 and16. A pair of pillow blocks 37 form a journal connection between thetorsion member and the bed plate 21. Each of the pillow blocks include abushing 38 of suitable resilient material such as neoprene to minimizenoise and Vibration.

An arm 39 which is outside the adjacent frame member is secured to eachend of the torsion member 36 and can be integral therewith as shown inthe drawing. Suitable means is provided on each end of the arm such as aball and socket joint 41 to form an articulated connection between theend of the arm and the rod 42. Suitable means is also provided on theother end of the rod 42 to form an articulated connection with themounting bracket or pad 43 such as the ball and socket joint 44.

Pad 43 is fixed to the axle 17 by suitable means such as the U-bolts 46which clamp over the extensions 47 of the pad. As shown in the drawing,the pad rests upon a semi-elliptical overload spring 48. The overloadspring 48 is spaced from a semi-elliptical load carrying spring 49 by aspacer block 51 and the load carrying spring 49 is supported upon theaxle 17 by saddle block 52. Both springs and the pad or mounting block43 are fixed to the axle 17 by a clamping plate 53 which is secured tothe lower ends of the U-bolts 46.

to use the work cage 29v atfthe side of the truck; As 7 described in myco-pending application SerialNo. 560,621,.

filed January 23, 19576;,'thelo'ad supporting s'tructure24 is rotatedabout the-verticalaxis provided by stud'shaft.

22 until the load supporting structure is in the proper angularposition. At the same time, the boom structure 7 27 maybe raised andextended until the work cage 29 p is at the desired position.

As soon as the center of gravity of the load supporting structure 24does not overlie the longitudinal axis of the vehicle, there-is atendency to tipthe bed plate 21 and the frame members 14 and 16 sidewaysandthis tendency increases as the center'of gravity is shifted a greaterdistahce from the longitudinal axis of the vehicle. This tipping isgenerally exaggerated because shifting *of'the center of gravity causescompression of the cushioning assembly on one side of the vehicle andexpansion of the cushioning assembly on the other side of the vehicle,In loadlifting equipment of this type, fwifthout stabilizing apparatus,the weight of the 'loadsupporting structure in itself is sufiicient totip over the vehicle when the boom structure is extending atsubstantially right angles to the longitudinal axis of the vehicle. V e

The stabilizing apparatus I have provided serves to generally stabilizethe framework of the equipment and also serves to" prevent overturningof the equipment.

With'my stabilizing apparatus as soon as the center of gravity isshifted from the longitudinal axis of the vehicle or sideways of thevehicle, the stabilizing assemblies function' in the following manner.The shifting of the center a of gravity from the longitudinal axis ofthe vehicle tends to cause compression of one cushioning assembly andexpansion of the other cushioning assembly fastened to the axle 17.Compression of the cushioning member 18 causes one of the arms 39 ofeach stabilizing assembly to be rotated in one directionwhereasexpansion of the other cushioning assembly causes the other of the armsof each stabilizing assembly to be rotated in an opposite direction tocause torsion to be applied to the member 36. Since rotation of the arms39 tends to twist the torsion member 36 in opposite directions;'thetorsion member 36 serves to inhibit rotational movement of the arms 39.and therefore the compression and expansion of the cushioning assemblies18. Thus, as the work cage 29 is moved sideways of the vehicle, theframe will be prevented from tippingany substantial amount by thestabilizing assemblies. The ball and socket connections 41 and 44 serveto accommodate any roll that may occur between the frame of the vehicleand the axle'17. l

, Although the" stabilizing assemblies prevent sideways movement of theframe relative to the axle 17, they do not prevent the normalfunctioning of the cushioning assemblies 18. For example, if, both ofthe rear wheels 13 strike a bump simultaneously, the cushioningassemblies 18' will cushion the shock and the torsion bars 36 will haveno effectbecause of the articulated connections I have provided withball and socket joints 41 and 44. However, if' only one of the rearWheels should strike a bump, the torsion bar will become effective and'will operate in a manner well known to those skilled in the the scopeof the present invention. For example, it may 4 7 a y a a. It will beapparent from the foregoing that I have provided lifting equipment withnove'l' apparatus forimprov ing the stability and. lifting? performanceof the lifting equipment and at the same time improving the ridabilityof the vehicular mount for the load carrying structure. The apparatusneed not be disconnected at any time and functions whether the vehicleis moving or stationary. "I'his particularly adapts the equipment foroperations where continuous movement-is required such as in the placingof a messenger andtelephone cable.

I claim:

1. In mobile lifting equipment of the type including a wheeled'vehicleand a'lift supporting structure carried by "the vehicle and adapted torotate about a vertical axis,

the vehicle having at least one wheel mounting axle generally underlyingsaid axis, and laterally spaced longitudinal frame members attached tothe axle by load supporting cushioning assemblies, means including, arigid bed plate serving .tocarry said structure, .thebed plate beingsupported by said frame members, a torsion member extending laterally ofthe frame members. adjacent said bed plate, means forming a journalconnection between said member and the bed plate, said member hav- 7vehicle having at least one wheel mounting axle generally a underlyingsaid axis, and laterallyvspaced longitudinal frame members attached tothe axle by load supporting cushioning assemblies, means including arigid bed plate serving to carry said structure, the bed plate beingsup-' ported by said frame members, a pair of torsion membersextending-laterally of the frame members and 'adjacent opposite sides of.said bed plate, means forming a journal connection between eachiof saidtorsion memf bers and the bed plate, said torsion members having armssecured to the ends of the same, and means forming an V and said axle.

articulated connection between the ends of the said ar'ms 4. In mobilelifting equipment of the type including a vehicle and a lift supportingstructure carried by the vehicle and adapted to rotate about a verticalaxis, the

vehicle having at least oneload carryingaxle generally underlying saidverticalaxis, and laterally spaced longi} tndinal frame members attachedto the axle by load supporting cushioning assemblies, means "including arigid bed plate for carrying saidstructure, the bed plate being fixed tosaid frame members, atorsion member extending laterally ofthe framemembers adjacent said bed plate, bearing means for journalling thetorsion member,

said bearing means being fixed relative to the frame membedesirableincertain instances to utilize only a single a stabilizingassembly in place ofithe two stabilizinghs semblies shown in thedrawing.

bers and the bed plate, said torsion member having arms secured to theends of the same, and means forming an articulated connection betweenthe ends of said arms and said axle.

5. In a mobile lifting equipment of the type including a vehicle and alift supporting structure carried by the vehicle and adapted to. rotate"about a vertical axis, the

. vehicle having at least one load carrying axle generally underlyingsaid vertical axis,.and laterally spaced-longitudinal framemembers-attached to the axle by loadsupporting cushioning assemblies,meansincluding a rigid bed plate for carrying said structure, the bedplate being fixed tosaid frame members, a torsion member extend inglaterally of the frame members adjacent said bed plate, and bearing'means rotatably mounting said torsion member;- said bearing means.beingfixed relative to the frame members and the bed plate, saidtorsion member 7 having arms secured to the ends of the same, the armsbeing outside the frame members, and means forming an articulatedconnection between the ends of the arms and said axle.

6. A mobile lifting equipment as in claim 5 wherein the ends of thetorsion members extend beyond the outer side edges of the frame members.

References Cited in the file of this patent UNITED STATES PATENTS2,231,285 Austin Feb. 11, 1941 2,300,237 Schroeter et a1 Oct. 27, 19422,325,089 Zeilman July 27, 1943 2,600,462 Bateman June 17, 1952

